Thanks to both of you for the recommendations. I will follow them.
Tom (Dr. Thomas S. Ligon) <mailto:thomassli...@gmail.com> thomassli...@gmail.com Frohnloher Str. 6a 81475 Muenchen Germany Tel. +49(89)74575075 From: sympy@googlegroups.com <sympy@googlegroups.com> On Behalf Of Aaron Meurer Sent: Sunday, August 7, 2022 7:42 AM To: sympy@googlegroups.com Subject: Re: [sympy] storing big integers as prime factors As Oscar pointed out, it's not clear that this would actually be more efficient. However, some things that could help, based on what you've said, are - Use Poly and any relevant Poly methods to represent and manipulate polynomial expressions - Make sure gmpy2 is installed. If it is, SymPy will automatically use it for much faster integer operations, especially when using Poly. - Rewrite your recursive function to operate non-recursively. Recursive functions are slower in Python than normal loops. Aaron Meurer On Sat, Aug 6, 2022 at 8:08 AM Thomas Ligon <thomassli...@gmail.com <mailto:thomassli...@gmail.com> > wrote: Is there any way to do this, perhaps just by saying that I want to keep prime factors instead of decimal digits? Background: I am writing software (using Python and SymPy) to calculate the coefficients of a power series. By using Rational(0) to initialize sums and Rational(1,2) to avoid getting a floating point, I have results that are always rational, specifically quotients of large integers and have reached the point where the integers have about 50 digits. I have a (fairly complex) recursive function that calculates the coefficient of x**(n+1) when the coefficients of x**n are known. When calculating the sum of two rational numbers, this most likely calculates the greatest common denominator, something which is sure to be hard. If all of the integers were always stored in terms of their prime factors instead of decimal digits, it would be much more efficient. Is there such a feature out there somewhere? -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com <mailto:sympy+unsubscr...@googlegroups.com> . To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/7171be2f-67a7-4d48-8eac-5d37571677c4n%40googlegroups.com <https://groups.google.com/d/msgid/sympy/7171be2f-67a7-4d48-8eac-5d37571677c4n%40googlegroups.com?utm_medium=email&utm_source=footer> . -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com <mailto:sympy+unsubscr...@googlegroups.com> . To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6K30P76B8J%2B4rBrqQ0bCzV0OHY%3DJjZjaKb4ZkWzRZUYoA%40mail.gmail.com <https://groups.google.com/d/msgid/sympy/CAKgW%3D6K30P76B8J%2B4rBrqQ0bCzV0OHY%3DJjZjaKb4ZkWzRZUYoA%40mail.gmail.com?utm_medium=email&utm_source=footer> . -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/005d01d8aa33%240800e500%241802af00%24%40gmail.com.
